scholarly journals Preparation and Characterization of Nanocrystalline TiO2 on Microsericite for High-Efficiency Photo-Energy Conversion of Methanol to Hydrogen

Crystals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 380 ◽  
Author(s):  
Huang ◽  
Wu ◽  
Nguyen ◽  
Nguyen
Keyword(s):  
Acetic Acid ◽  
Hydrogen Production ◽  
Energy Conversion ◽  
High Efficiency ◽  
Uv Light ◽  
Sol Gel ◽  
Nitrogen Adsorption ◽  
Absorption Spectrometry ◽  
Nanocrystalline Tio2 ◽  
Bet Theory

TiO2 and TiO2/sericite photocatalysts were successfully synthesized via the sol-gel method by adding a varying amount of acetic acid. The effect of acetic acid on TiO2 and TiO2/sericite photocatalysts was studied. The crystallite size, surface morphology, chemical composition, specific surface area, surficial functional groups, and light absorbance of the prepared photocatalysts were revealed by the analysis of X-ray diffraction (XRD), scanning electron microscope-energy dispersive spectrometry (SEM-EDS), nitrogen adsorption-desorption isotherms by using BET theory (Brunauer–Emmett–Teller), Fourier-transform infrared spectroscopy (FTIR), and UV-Vis absorption spectrometry. Photo-energy conversion of methanol to hydrogen was also conducted over the prepared photocatalysts. The best hydrogen production was achieved by using the TiO2/sericite photocatalyst to give a hydrogen production rate of 1424 μmol/g·h in 6 h of UV-light irradiation.

Role of Nanocrystalline Titania Phases in the Photocatalytic Oxidation of NO at Room Temperature

2010 ◽  
Vol 132 ◽  
pp. 96-104
Author(s):  
S. Castillo ◽  
R. Carrera ◽  
R. Camposeco ◽  
P. Del Angel ◽  
J.A. Montoya ◽  
...  
Keyword(s):  
Photocatalytic Oxidation ◽  
Room Temperature ◽  
Uv Light ◽  
Anatase Phase ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Nitrogen Adsorption ◽  
Nanocrystalline Tio2 ◽  
Oxidation Activity

Nanocrystalline TiO2 powders were prepared by the sol-gel method and evaluated in the NO photocatalytic oxidation. Samples annealed at 200 and 500°C (TiO2-P-200, TiO2-P-500) were characterized by nitrogen adsorption, XRD-Rietveld refinements, TEM, FTIR and UV-vis spectroscopies. The photocatalytic test of the sol-gel TiO2 samples was carried out in an insulated chamber with 10 ppm of NO, using a 365-nm UV light lamp; the test results were compared with those obtained with a commercial catalyst (P25). Improved photoactivity (89 % of NO oxidized in 60 min) was obtained with the TiO2-P-200 solid which showed high surface area, small crystallite size, higher amount of OH and highly abundant brookite phase (37.2 %) coexisting with the anatase phase (62.8 %). The photo-oxidation activity of the sol-gel catalyst annealed at 500 °C (TiO2-P-500) showed changes in its textural and morphologic properties and therefore, less photoactivity. Sol-gel photocatalysts could be a good option for abating pollution in both indoor and outdoor environments at room temperature.

Sol-Gel Preparation of Bi2InTaO7 and its Photocatalytic Behavior for Organic Compounds Degradation

2010 ◽  
Vol 658 ◽  
pp. 491-494 ◽  
Author(s):  
Leticia M. Torres-Martínez ◽  
Isaías Juárez-Ramírez ◽  
Juan S. Ramos-Garza ◽  
Francisco Vázquez-Acosta ◽  
Soo Wohn Lee
Keyword(s):  
Organic Compounds ◽  
High Efficiency ◽  
Uv Light ◽  
Sol Gel ◽  
Type Structure ◽  
Alizarin Red S ◽  
Green Tide ◽  
Alizarin Red ◽  
Pyrochlore Type ◽  
Degradation Reaction

In this work it was carried out the synthesis of Bi2InTaO7 pyrochlore-type structure compound by the sol-gel method. By X-Ray powder diffraction the sol-gel compound calcined at 600°C showed the pyrochlore-type structure phase and by scanning electron microscopy its morphology revealed the presence of particles with size lower than 1 micron. Its chemical elemental composition was determined by EDS analysis. Results of SBET area and Eg values of this compound suggested higher properties than those obtained by the compound prepared by solid state reaction. Bi2InTaO7 sol-gel was used as active photocatalyst on the degradation reaction of organic compounds such as Alizarin Red S, and Red and Green Tide, under UV-light. Half time life results showed that Bi2InTaO7 sol-gel compound could be a good candidate for the degradation of organic compounds because after few minutes showed high efficiency on the degradation reaction of Alizarin Red S (t1/2 = 30 min), and Green Tide inactivation (t1/2 = 17 min).

scholarly journals Photocatalytic Hydrogen Production Under Near-UV Using Pd-Doped Mesoporous TiO2 and Ethanol as Organic Scavenger

Catalysts ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 33 ◽  
Author(s):  
Bianca Rusinque ◽  
Salvador Escobedo ◽  
Hugo de Lasa
Keyword(s):  
Hydrogen Production ◽  
Uv Light ◽  
Sol Gel ◽  
Chemical Reactor ◽  
Morphological Properties ◽  
Soft Template ◽  
Quantum Yields ◽  
Metal Doped ◽  
The University ◽  
Energy Balances

Photocatalysis can be used advantageously for hydrogen production using a light source (near-UV light), a noble metal-doped semiconductor and an organic scavenger (2.0 v/v% ethanol). With this end, palladium was doped on TiO2 photocatalysts at different metal loadings (0.25 to 5.00 wt%). Photocatalysts were synthetized using a sol-gel method enhancing morphological properties with a soft template precursor. Experiments were carried out in the Photo-CREC Water II reactor system developed at CREC-UWO (Chemical Reactor Engineering Centre- The University of Western Ontario) Canada. This novel unit offers hydrogen storage and symmetrical irradiation allowing precise irradiation measurements for macroscopic energy balances. Hydrogen production rates followed in all cases a zero-order reaction, with quantum yields as high as 30.8%.

scholarly journals PHOTOCATALYTIC DEGRADATION OF INDIGO CARMINE BY TiO2/ACTIVATED CARBON DERIVED FROM WASTE COFFEE GROUNDS

2016 ◽  
Vol 16 (1) ◽  
pp. 21-26
Author(s):  
Irwan Irwan ◽  
Surya Lubis ◽  
Muliadi Ramli ◽  
Sheilatina Sheilatina
Keyword(s):  
Activated Carbon ◽  
Uv Light ◽  
Sol Gel ◽  
Indigo Carmine ◽  
Nitrogen Adsorption ◽  
Structural Features ◽  
Solar Light ◽  
Titanium Tetraisopropoxide ◽  
X Ray ◽  
Coffee Grounds

TiO2/activated carbon derived from waste coffee grounds (TiO2/WCGAC) has been prepared by a sol gel method . Waste coffee ground was chemically activated using hydrochloric acid 0.1 M solution and modified with titanium tetraisopropoxide as TiO2 precursor. The structural features of the photocatalyst was investigated by X-ray diffraction (XRD), scanning electron microscope energy dispersive X-ray spectroscopy (SEM EDX),  Fourier transform infrared spectroscopy (FT-IR) and nitrogen adsorption-desorption. The XRD results showed that TiO2 is anatase and rutile phase, while FTIR spectra confirmed the presence of  Ti-O groups. The specifics surface area of TiO2/WCGAC was higher than that of activated carbon derived from waste coffee grounds. The photocatalytic activity of TiO2/WGCAC has been evaluated for degradation of indigo carmine solution under UV and solar light irradiation. It was found that degradation percentage of indigo carmine under solar light was higher than that of under UV light.

scholarly journals Clean 3,4-Dihydropyrimidones Synthesis via Biginelli Reaction over Supported Molybdenum: Structural and Textural Characteristic of αMoO3

2020 ◽  
Vol 15 (3) ◽  
pp. 698-713
Author(s):  
Ouzna Kheffache ◽  
Cristina Lopez-Olmos ◽  
Inmaculada Rodriguez-Ramos ◽  
Ouiza Cherifi
Keyword(s):  
Electron Microscopy ◽  
High Efficiency ◽  
Biginelli Reaction ◽  
Sol Gel ◽  
Nitrogen Adsorption ◽  
Active Species ◽  
One Pot ◽  
Textural Characteristic ◽  
X Ray ◽  
Heterogeneous Catalytic

A one-pot three-component synthesis of dihydropyrimidinones (DHPMs) via Biginelli reaction was carried out at 100 °C using benzaldehyde, ethyl acetoacetate and urea as reactants, in the presence of ethanol and free solvent, in heterogeneous catalytic medium. The Mo (30 wt%) metal oxides (Al2O3, SiO2 or MgO) used catalysts were prepared by sol-gel, impregnation and microemulsion methods and characterized by X-Ray Diffraction (XRD), Fourier Transform Infra Red (FTIR), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Energy Dispersive X-ray (EDX), Nitrogen Adsorption - Brunauer-Emmett-Teller (BET), and NH3-Temperature Programmed Desorption (TPD) methods. The Mo-SiO2 sample prepared by the sol-gel method exhibited the highest DHPM yield (87%), in free solvent with a reaction time of 30 min. The high efficiency, in the Biginelli reaction, of the Mo-SiO2 catalyst is due to its structural, textural and acid properties. Highly dispersed αMoO3 species of orthorhombic structure having a high contribution of strong acidic sites would be the active species in the Biginelli synthesis  Copyright © 2020 BCREC Group. All rights reserved 

scholarly journals Octahedral Shaped PbTiO3-TiO2 Nanocomposites for High-Efficiency Photocatalytic Hydrogen Production

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2295
Author(s):  
Simin Yin ◽  
Shun Liu ◽  
Yongfeng Yuan ◽  
Shaoyi Guo ◽  
Zhaohui Ren
Keyword(s):  
Hydrogen Production ◽  
High Efficiency ◽  
Uv Light ◽  
Evolution Rate ◽  
Tetrabutyl Titanate ◽  
H2 Evolution ◽  
Tio2 Nanocrystals ◽  
Photocatalytic Hydrogen Production ◽  
Alcohol Water ◽  
Vis Spectroscopy

In this work, octahedral shaped PbTiO3-TiO2 nanocomposites have been synthesized by a facile hydrothermal method, where perovskite ferroelectric PbTiO3 nanooctahedra were employed as substrate. The microstructures of the composites were investigated systemically by using XRD, SEM, TEM and UV-Vis spectroscopy. It was revealed that anantase TiO2 nanocrystals with a size of about 5 nm are dispersed on the surface of the {111} facets of the nanooctahedron crystals. Photocatalytic hydrogen production of the nanocomposites has been evaluated in a methanol alcohol-water solution under UV light enhanced irradiation. The H2 evolution rate of the nanocomposites increased with an increased loading of TiO2 on the nanooctahedra. The highest H2 evolution rate was 630.51 μmol/h with the highest concentration of TiO2 prepared with 2 mL tetrabutyl titanate, which was about 36 times higher than that of the octahedron substrate. The enhanced photocatalytic reactivity of the nanocomposites is possibly ascribed to the UV light absorption of the nanooctahedral substrates, efficient separation of photo-generated carriers via the interface and the reaction on the surface of the TiO2 nanocrystals.

Facile Synthesis and Enhanced Photocatalysis of Sm Doped TiO2

2012 ◽  
Vol 490-495 ◽  
pp. 3272-3276 ◽  
Author(s):  
Hong Tao Gao ◽  
Wen Chao Liu ◽  
Guang Jun Liu
Keyword(s):  
Photocatalytic Activity ◽  
Uv Light ◽  
Sol Gel ◽  
Light Irradiation ◽  
X Ray Diffraction ◽  
Nanocrystalline Tio2 ◽  
Ultrasonic Assisted ◽  
Optimal Doping Concentration ◽  
Uv Visible ◽  
Sol Gel Synthesis

Sm doped nanocrystalline TiO2 powers were prepared by ultrasonic assisted sol-gel synthesis. The samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and UV-visible diffuse reflectance spectra (DRS), respectively. Both of undoped TiO2 and Sm-TiO2 samples exclusively consist of primary anatase crystallites, which further form spherical aggregates with average diameters ranging from 11 to 19 nm. The photocatalytic activity of Sm-TiO2 was investigated on the photocatalytic degradation of methyl orange (MO) aqueous solution under UV visible light irradiation. Sm doping improves effectively the photocatalytic activity under UV light irradiation with an optimal doping concentration of 0.5%. The photocatalytic mechanisms of Sm-TiO2 catalysts were tentatively discussed

The use of high-resolution FESEM to study solid-state phase transformations and reactions

1994 ◽  
Vol 52 ◽  
pp. 1028-1029
Author(s):  
P. G. Kotula ◽  
D. D. Erickson ◽  
C. B. Carter
Keyword(s):  
Solid State ◽  
High Resolution ◽  
Phase Transformations ◽  
High Efficiency ◽  
Sol Gel ◽  
Quantitative Information ◽  
Solid State Reactions ◽  
Critical Dimensions ◽  
Backscattered Electrons ◽  
Backscattered Electron

High-resolution field-emission-gun scanning electron microscopy (FESEM) has recently emerged as an extremely powerful method for characterizing the micro- or nanostructure of materials. The development of high efficiency backscattered-electron detectors has increased the resolution attainable with backscattered-electrons to almost that attainable with secondary-electrons. This increased resolution allows backscattered-electron imaging to be utilized to study materials once possible only by TEM. In addition to providing quantitative information, such as critical dimensions, SEM is more statistically representative. That is, the amount of material that can be sampled with SEM for a given measurement is many orders of magnitude greater than that with TEM.In the present work, a Hitachi S-900 FESEM (operating at 5kV) equipped with a high-resolution backscattered electron detector, has been used to study the α-Fe2O3 enhanced or seeded solid-state phase transformations of sol-gel alumina and solid-state reactions in the NiO/α-Al2O3 system. In both cases, a thin-film cross-section approach has been developed to facilitate the investigation. Specifically, the FESEM allows transformed- or reaction-layer thicknesses along interfaces that are millimeters in length to be measured with a resolution of better than 10nm.

STRUCTURAL, OPTICAL PROPERTIES AND PHOTOCATALYTIC ACTIVITY OF NANOCRYSTALLINE TiO2 THIN FILMS DEPOSITED BY SOL-GEL SPIN COATING

2019 ◽  
Vol 7 (1) ◽  
pp. 28
Author(s):  
KOMARAIAH DURGAM ◽  
RADHA EPPA ◽  
REDDY M. V. RAMANA ◽  
KUMAR J. SIVA ◽  
R. SAYANNA ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Photocatalytic Activity ◽  
Spin Coating ◽  
Sol Gel ◽  
Tio2 Thin Films ◽  
Nanocrystalline Tio2

scholarly journals Construction of the Cellulose Nanofibers (CNFs) Aerogel Loading TiO2 NPs and Its Application in Disposal of Organic Pollutants

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1841
Author(s):  
Kang Li ◽  
Xuejie Zhang ◽  
Yan Qin ◽  
Ying Li
Keyword(s):  
High Efficiency ◽  
Sol Gel ◽  
Cellulose Nanofibers ◽  
Three Dimensional ◽  
Good Mechanical Property ◽  
Polar Groups ◽  
Dimensional Network ◽  
Natural Polysaccharide ◽  
Valuable Method ◽  
Adsorption Capability

Aerogels have been widely used in the adsorption of pollutants because of their large specific surface area. As an environmentally friendly natural polysaccharide, cellulose is a good candidate for the preparation of aerogels due to its wide sources and abundant polar groups. In this paper, an approach to construct cellulose nanofibers aerogels with both the good mechanical property and the high pollutants adsorption capability through chemical crosslinking was explored. On this basis, TiO2 nanoparticles were loaded on the aerogel through the sol-gel method followed by the hydrothermal method, thereby the enriched pollutants in the aerogel could be degraded synchronously. The chemical cross-linker not only helps build the three-dimensional network structure of aerogels, but also provides loading sites for TiO2. The degradation efficiency of pollutants by the TiO2@CNF Aerogel can reach more than 90% after 4 h, and the efficiency is still more than 70% after five cycles. The prepared TiO2@CNF Aerogels have high potential in the field of environmental management, because of the high efficiency of treating organic pollutes and the sustainability of the materials. The work also provides a choice for the functional utilization of cellulose, offering a valuable method to utilize the large amount of cellulose in nature.

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